Radio frequency-microelectromechanical systems (RF-MEMS) capacitive switch (CS) based systems have attracted a significant interest in recent years. These RF-MEMS CS systems provide excellent RF characteristics (such as high linearity and low losses), as well as low power consumption.
A typical RF-MEMS CS system 10 found in the prior art is depicted in FIG. 10. Such an RF-MEMS CS may find diverse applications in radar systems, wireless communication, instrumentation, etc. Compared to solid state switches, RF-MEMS switches offer the advantages of low power consumption, low insertion and return loss, extremely high linearity, and excellent isolation. Several disadvantages have been well documented in the prior art including but not limited to reaching and maintain a high level of reliability. One source of degradation of RF-MEMS CSs is the result of dielectric charging by virtue of a built-in charge that causes a shift in the capacitance-voltage characteristics. Additionally, poor reliability related to mechanical creep, and fatigue amongst other issues, continue to hinder the large scale deployment of RF-MEMS switches. Another key reliability concern is the impact velocity—the velocity with which a movable electrode 12 (see FIG. 10) impacts a dielectric layer 14 in an electrostatically actuated (voltage source 16) RF-MEMS CS. This impact damages the dielectric layer 14 and increases the adhesion forces which may eventually lead to malfunction of the switch due to stiction.
To address the challenges in reliability of a CS, novel approaches are needed to address the above-described dielectric degradation caused by impacting of a moveable electrode against a dielectric layer.